Grounding architectures for enabling ground fault ride-through capability in DC microgrids

Fault Management in DC Microgrids: A Review of Challenges, Countermeasures, and Future Research Trends

“…The issues may arise with high impedance ground faults which may be tough to detect. The high impedance ground fault detection is the main problem for DC MGs protection [24]; for this purpose, the power converter fault current with the DC link capacitor voltage is used to ensure reliable operation [25]. In [26], the zone base DC MGs consist of intelligent electronic devices (IEDs), mainly capable of detecting fault current in a DC bus-segment to avoid system shutdown by isolating the faulty segment.…”

“…The major challenges for fault protection of DC MGs can be elaborated as: [31], fast and efficient fault detection strategies [32], fault-classification [33], current limiting and ease of fault location [34], and a proper DCCB are essential [35]. Grounding in DC MGs is related to various system considerations such as design purpose, grid reliability under normal circumstances, minimize leakage current [24], ground fault identification [24], and maximize the equipment safety under fault conditions [36]. Given that, a novel current grounding method has to be introduced which could emphasize the fault detection capability of the DC system [24].…”

“…Grounding in DC MGs is related to various system considerations such as design purpose, grid reliability under normal circumstances, minimize leakage current [24], ground fault identification [24], and maximize the equipment safety under fault conditions [36]. Given that, a novel current grounding method has to be introduced which could emphasize the fault detection capability of the DC system [24]. Based on the current features pertaining to the DC faults, an appropriate and reliable method is the need of the hour to maintain stability and to restrain any damage to equipment.…”

Modular Smart Transformer Topology for the Interconnection of Multiple Isolated AC and DC Grids

“…As the most important feature of the isolation, disturbances can be prevented from passing through the grids and it prevents high fault and body currents [7]- [9]. In the case with isolation, high resistance grounding schemes can be applied to provide a safer operation of the LVDC grid.…”

Fault tolerance enhancement of the PV module system by improving the topology and control strategy

“…Third, for the grounding fault problem, it is normally recommended that the ground resistance would be very small in the large PV station in order to protect the safety of the staff and the electronic devices [23][24][25]. Normally, the grounding fault appears among the PV modules due to the loosening lines or aging insulation, especially in the rainstorm or lightning weather [26][27][28]. For example, Devarakonda et al [26] demonstrated that the grounding fault in PV strings would cause a serious mismatch between the terminal voltages of the faulty string and other strings, and the faulty PV string was operated as a load, which would increase the power loss and damage the stable operation of other PV strings.…”